It's not like Pamela Gregg was a stranger to helping out the underdog. She thought she knew what kinds of pooches linger the longest in animal shelters: Older dogs, abused dogs, sick or injured dogs — dogs like George Bailey, the hound mix she'd rescued after he'd been struck by a car.

But black dogs? While searching for a companion for George Bailey, Gregg was shocked to see a banner on an Ohio animal shelter's Web site that detailed how tough it is for big dogs with black coats to find homes.

"It said something like, 'We know that you people prefer colors, but we've got wonderful black dogs here, won't you please consider them?'" recalls Gregg, who's 49 and lives in Xenia, Ohio. "I was shocked, because I think that black dogs are beautiful — and I couldn't believe people would not get a dog based on its color."

To the uninitiated, the idea seems so strange — doggie discrimination? But among those in animal rescue circles, the phenomenon is commonplace enough to have earned its own name: "black dog syndrome."

"There's not a lot of that type of statistics on many aspects of sheltering," says Kim Intino, the director of animal sheltering issues for the Humane Society of the United States. "But I think that every person that has worked in a shelter can attest that in shelters animals with black coats can be somewhat harder to adopt out — or to even get noticed."

Even after a year had passed at a Los Angeles animal shelter, no one had noticed Estelle. Except, of course, for the staff; they fawned over the big black dog and her gentle demeanor. They started letting Estelle roam the office during the day, which let one couple see her in action — outside her cage and calmly interacting with people. They fell for her, and took her home.

But not every black dog is lucky enough to get that kind of special attention, says Madeline Bernstein, the president of the Society for the Prevention of Cruelty to Animals in Los Angeles.

"They're the hardest to adopt out, they're in the shelters the longest and therefore, they're most likely to be euthanized if nothing happens," Bernstein says. (Breeders don't tend to face this problem at the level that shelters do, simply because they have fewer animals to deal with than a city shelter that takes strays in every day.)

Bernstein has plenty of theories about why people might not want black dogs in animal shelters. It's mostly an unconscious thing, she says, which may explain why black cats have the same problems finding a home. People who are aware of superstitions about black cats (don't let them cross your path!) may also be unconsciously harboring superstitions about black dogs.

In British folklore, such as stories by Sir Arthur Conan Doyle and Sir Walter Scott, the black dog is a creepy, spectral figure that haunts cemeteries and is an omen of death. (Non-lit geeks who've never heard of those stories have at least seen "Harry Potter and the Prisoner of Azkaban," in which a big black dog called the Grim stalks Harry.) Another Englishman, Winston Churchill, battled serious bouts of depression which he called "the black dog."

Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

But some speculate that black dogs just don't have the right look to catch the eye of potential adopters.

"Black dogs might appear older; even when they're young, they have bits of facial hair that may be white or gray," Bernstein says. And the ignored breeds are often those who simply look a little big and scary, and whose bad reputations may have preceded them, such as Rottweiler, Doberman pinscher and pit bull mixes.

Bernstein says some people turn in their black dogs to the shelters because they've gotten new furniture and don't like the dark fur their pet sheds.

Too hard to see
But it may be the simplest reason that's costing these dogs a good home — their black coats can make them invisible in poorly lit kennels. (Same problem happens with amateur photos on shelters' Web sites, which is how many people find the dog they intend to adopt.)

"Sometimes if a potential adopter sees a whole row of black dogs, they think, 'Maybe they're not being adopted for a good reason. Maybe there's something wrong with these dogs,'" Bernstein says.

So volunteers at some shelters put extra energy into getting their black dogs noticed. They place brightly colored, eye-catching blankets and toys in their kennels. At Bernstein's shelters, they tie pink ribbons around the necks of the girls, and fasten big bow ties around the necks of the boys.

"In our kennels, the black dogs are all decked out," Bernstein says.

One shelter in Kettering, Ohio, the Society for the Improvement of Conditions for Stray Animals even ran a special discount on black dogs in February, slashing adoption fees in half after executive director Rudy Bahr realized that out of his shelters' 42 dogs, 28 of them were big and black. Bahr instructs his employees in the same sort of tactics Bernstein's shelters take to attract attention to black dogs, like tying bandannas around their necks and taking the dogs to a well-lit area outside to have their photo taken for their Web site.

It was that kind of photo on the shelter's site that attracted Gregg's attention as she continued her search for a companion for George Bailey. "I was trolling through their pictures and there she was," Gregg says. "She was a hound mix like George Bailey, but Molly is sleek, shiny black. As soon as I saw her I completely fell in love. I couldn't get in my car fast enough."

Molly and Bailey turned out to be a perfect match, and if Gregg someday rescues another dog, she says she'll definitely go for a big black dog.

"If and when I get another dog, I will probably deliberately look for another black dog, only because I've learned of black dog syndrome," Gregg says. "Bring 'em my way, because I love 'em."